#!/usr/bin/perl

# notmuch-extract-patch -- extract a git patch series from notmuch
#
# Copyright (C) 2020 Sean Whitton
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

use 5.028;
use strict;
use warnings;

use IO::Pipe;

my (@ARGV_notmuch, @ARGV_extract, $no_more_extract);
for (@ARGV) {
    if (/\A--\z/) {
        $no_more_extract = 1;
    } elsif (/\A-/ and not $no_more_extract) {
        push @ARGV_extract, $_;
    } else {
        push @ARGV_notmuch, $_;
    }
}

$SIG{CHLD} = "IGNORE";
my $pipe = IO::Pipe->new;

my $notmuch_pid = fork;
die "fork() failed: $!" unless defined $notmuch_pid;
unless ($notmuch_pid) {
    $pipe->writer;
    open STDOUT, ">&=", $pipe->fileno
      or die "couldn't reopen child's STDOUT: $!";
    exec qw(notmuch show --format=mbox), @ARGV_notmuch;
}
$pipe->reader;
open STDIN, "<&=", $pipe->fileno
  or die "couldn't reopen parent's STDIN: $!";
exec "mbox-extract-patch", @ARGV_extract;